package com.javacoding.huawei;

import java.util.BitSet;
import java.util.Scanner;

public class HJ10字符个数统计 {
    public static void main(String[] args)
    {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        BitSet bitSet = new BitSet(128);
        for(char c:line.toCharArray()){
            if(!bitSet.get(c)){
                bitSet.set(c);
            }
        }
        System.out.println(bitSet.cardinality());
    }
}
